Shares in some of the country’s largest mobile phone carriers dropped in Tokyo after the communications minister accused the companies of deploying a bait-and-switch tactic in cutting the costs of mobile phone plans.

Reducing the nation’s hefty mobile phone bills has been a priority for the administration of Prime Minister Yoshihide Suga, but carriers have largely avoided making cuts to plans offered by their mainstay operations. Instead, they’ve made cuts at their so-called subbrands — cheaper operations wholly owned by the carriers, such as KDDI Corp.’s UQ and SoftBank Corp.’s Yahoo Mobile. The subbrands offer discount plans but often not the latest phones, and are popular with students and those using less data.

"There have been no cheap plans announced at all for the main brands, which are used by most customers,” Ryota Takeda, the minister of internal affairs and communications, told a news conference in Tokyo on Friday. "They’re ‘promising mutton but selling dog,’” he added, using an expression that could also be translated as "selling vinegar as wine” or "a pig in a poke.”